Carbon isotope detection device and application thereof

Abstract

The invention discloses a carbon isotope detection device and application thereof, and belongs to the technical field of environmental monitoring. The carbon isotope detection device provided by the invention comprises an anaerobic high-temperature pyrolysis device, a CO2 vacuum capture device, a CO2 purification device, a CO2 measurement device and a CO2 storage device, wherein the anaerobic high-temperature pyrolysis device comprises a pyrolysis bin, an oxidation bin, a first tubular furnace, a second tubular furnace, a vacuum pressure gauge and a flow regulating valve; according to the invention, the technology of anaerobic pyrolysis of organic matters and aerobic combustion of pyrolysis residues of organic matters is integrated with the technology of dynamic quantification of CO2 capture, static CO2 purification, measurement and storage, and a more reliable research material is provided for analysis of the ratio of accelerator mass spectrum 14C / 12C to stable isotope mass spectrum 13C / 12C.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon isotope detection, and in particular relates to a carbon isotope detection device and application thereof. Background Art

[0002] Preparation of high purity representative CO2 is accelerator mass spectrometry 14 C dating and traditional stable carbon isotope analysis. Plant fragments, charcoal, and sediments preserved in geological sections and archaeological sites undergo physical adsorption and chemical reactions during burial, mixing organic tissues / components from different periods and sources. It is difficult to distinguish them with laboratory pretreatment methods. In many cases, they are directly burned to produce total CO2, which obviously cannot meet the needs of cutting-edge research. Some laboratories have begun to use a mixture of low-concentration oxygen and high-concentration inert gas under step-by-step heating to "pyrolyze" sediment organic carbon to produce so-called CO2 of different "organic components" to study the hot topic - the mechanism of organic carbon cycle. However, low-concentration oxidation is still a slow combustion process. As long as the combustion time is long enough, organic components with strong carbon bond structures will also be partially oxidized to form CO2. In other words, "pyrolysis" in a low-oxygen environment is not only a function of temperature, but also a function of combustion time. Therefore, this technology actually produces CO2 with mixed components of organic carbon molecules with different proportions of carbon bonds from strong to weak, and the time required for low-oxygen "pyrolysis" is subjective and determined by experience. Summary of the invention

[0003] In response to the above-mentioned prior art, the present invention provides a carbon isotope detection device and its application, which integrates the pyrolysis residue (graphite-like black carbon) technology of anaerobic pyrolysis of organic matter and aerobic combustion of organic matter with the dynamic quantitative CO2 capture-static CO2 purification-measurement-storage technology.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a carbon isotope detection device, including an anaerobic high-temperature pyrolysis device, a CO2 capture device, a CO2 purification device, a CO2 measuring device and a CO2 storage device; the anaerobic high-temperature pyrolysis device includes a pyrolysis chamber, an oxidation chamber, a No. 1 tubular furnace, a No. 2 tubular furnace vacuum pressure gauge and a flow regulating valve; the pyrolysis chamber and the oxidation chamber are high-temperature resistant quartz tubes, the diameter of the pyrolysis chamber is smaller than the diameter of the oxidation chamber, the oxidation chamber is sleeved outside the pyrolysis chamber and the two are connected by a three-way joint and a conversion joint, the outer end of the pyrolysis chamber is an argon / oxygen inlet, and the inner end with a reduced diameter is a gas outlet, the gas outlet is located in the oxidation chamber, and two copper columns are arranged downstream of the gas outlet; one end of the oxidation chamber connected to the three-way joint is an oxygen inlet, and the other end is a gas outlet, the gas outlet is connected to the vacuum pressure gauge, and the vacuum pressure gauge is provided with a flow regulating valve.

[0005] Based on the above technical solution, the present invention can also be improved as follows.

[0006] Furthermore, the two tubular furnaces are both mounted outside the oxidation chamber, and tubular furnace No. 1 is mounted at the overlap of the oxidation chamber and the pyrolysis chamber, and tubular furnace No. 2 is located between tubular furnace No. 1 and the vacuum pressure gauge.

[0007] Furthermore, a conversion joint is provided on the flow regulating valve, and the conversion joint is connected to the CO2 vacuum capture device through a pipeline.

[0008] Furthermore, the CO2 vacuum capture device includes a U-shaped main tube and a glass tube; two arms of the U-shaped main tube extend into the lower part of the glass tube and are provided with a liquid nitrogen cooling device, and the glass tubes are respectively connected to the middle part of the U-shaped main tube.

[0009] Furthermore, the CO2 purification device is a low-temperature high-vacuum gas purifier, and is connected to the CO2 vacuum capture device ( through a stopcock.

[0010] Further, the CO2 measuring device is a calibrated barometer and is connected to the CO2 purification device via a stopcock.

[0011] Furthermore, the CO2 storage device is connected to the CO2 measuring device via a stopcock.

[0012] The beneficial effects of the present invention are as follows: the present invention integrates the pyrolysis residue (graphite-like black carbon) technology of anaerobic pyrolysis organic matter and aerobic combustion organic matter with the dynamic quantitative CO2 capture-static CO2 purification-measurement-storage technology, that is, all gases produced by the pyrolysis system at a pressure slightly higher than the atmospheric pressure are converted into vacuum through a needle valve and liquid nitrogen is used to effectively capture CO2 while removing other gases, and a new type of efficient equipment is developed. The present invention is the first to decompose organic molecular groups with the same carbon bond binding energy in a true sense, which is a new type of equipment for accelerator mass spectrometry. 14 C dating and stable carbon isotope analysis provide a reliable research method with theoretical research value. At the same time, the present invention can also extract organic carbon components with the same chemical bond valence energy to prepare CO2 for accelerator mass spectrometry. 14 C / 12 C and stable isotope mass spectrometry 13 C / 12 C ratio analysis provides more reliable research materials.

[0013] The invention also discloses the application of the carbon isotope detection device in geological and ecological detection.

[0014] Further, the application comprises the following steps:

[0015] S1: placing organic matter in a pyrolysis chamber, introducing inert gas into the pyrolysis chamber, and introducing oxygen into the oxidation chamber;

[0016] S2: raising the temperature of tube furnace No. 1 to 700-800° C. and maintaining the temperature of tube furnace No. 2 at 750° C. to obtain a pyrolysis residue;

[0017] S3: The inert gas in the pyrolysis chamber is replaced with oxygen, the temperature of tube furnace No. 1 is changed to 650-750°C, the temperature of tube furnace No. 2 is maintained at 750°C, and the pyrolysis residue is burned to obtain CO2, which is then tested by passing through the CO2 vacuum capture device, CO2 purification device, CO2 measuring device and CO2 storage device in sequence.

[0018] The beneficial effect of the present invention is that the carbon isotope detection device provided by the present invention performs accelerator mass spectrometry dating analysis on the active (low temperature) - stubborn carbon (high temperature) (or labile-recalcitrant) of anaerobic pyrolysis of organic matter in the geological period and the inert (high temperature) carbon (inert) component produced by aerobic combustion of combustion pyrolysis residues (black carbon), so as to quickly and efficiently grasp the geological age and other information, and plays a positive role in the study of geological ecology. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the design drawing of the oxygen-free high-temperature pyrolysis device in the carbon isotope detection device;

[0020] Figure 2 Design drawings of the CO2 vacuum capture device, CO2 purification device, CO2 measurement device and CO2 storage device in the carbon isotope detection device;

[0021] Figure 3 This is a picture of an organic sample being converted into graphite-like ultra-high purity black carbon material after high-temperature oxygen-free pyrolysis;

[0022] Figure 4 This is the experimental result diagram of the degradation reaction of organic carbon components in the anaerobic pyrolysis temperature range;

[0023] Figure 5 The results of the accelerator carbon-14 dating test of different organic carbon components of black carbon produced by anaerobic pyrolysis and aerobic combustion pyrolysis of four Northeastern black soil farmland profile samples;

[0024] Figure 6 This is the result of the accelerator carbon-14 dating test of different organic carbon components of black carbon produced by anaerobic pyrolysis and aerobic combustion pyrolysis of modern Yellow River delta sediments (after 1850);

[0025] Figure 7 This is the result of the accelerator carbon-14 dating test of different organic carbon components of black carbon produced by anaerobic pyrolysis and aerobic combustion pyrolysis of loess profile samples in Weinan, Shaanxi Province, in the southern part of the Loess Plateau;

[0026] Figure 8 This is the result of the accelerator carbon-14 dating test of different organic carbon components of black carbon produced by anaerobic pyrolysis and aerobic combustion pyrolysis of the organic carbon cover layer on the rock surface exposed in the karst area of ​​Guizhou;

[0027] Among them, 1 is an oxygen-free high-temperature pyrolysis device, 2 is an oxidation chamber, 3 is a pyrolysis chamber, 4 is a three-way joint, 5 is tube furnace No. 1, 6 is tube furnace No. 2, 7 is a vacuum pressure gauge, 8 is a flow regulating valve, 9 is a conversion joint, 10 is a conversion joint, 11 is a CO2 vacuum capture device, 12 is a CO2 purification device, 13 is a CO2 measuring device, and 14 is a CO2 storage device. DETAILED DESCRIPTION

[0028] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0029] Example 1

[0030] The oxygen-free high-temperature pyrolysis device 1 of the present invention is as follows Figure 1 As shown, a certain length of 9.6 mm diameter quartz glass tube (pyrolysis chamber 3) is thinned at one end and the thin end is inserted into a certain length of 13 mm diameter quartz glass tube (oxidation chamber 2), and two high temperature resistant quartz tubes of different thicknesses are sealed with a 13 mm UltraTorr tee joint 4 and a 9.6 mm UltraTorr conversion joint 10, and the other end of the tee joint 4 is converted to a 3 mm diameter ferrule interface to connect ultra-high purity oxygen to provide oxygen for the oxidation chamber. The pyrolysis chamber 3 is converted to a 3 mm diameter ferrule interface by UltraTorr to seal the thinned quartz glass at one end and provide ultra-high purity argon or oxygen at the same time, and the oxidation copper column and the reduction copper column (isolated by quartz wool) are filled in the gas outlet at the other end of the oxidation chamber 2 in a front-to-back order, and its port is sealed with a 13 mm UltraTorr tee, and the other two interfaces of the tee are installed with a 13 mm diameter vacuum pressure gauge 7 and a 13 mm interface flow control valve 8, and the other end of the flow control valve is converted with a 3 mm diameter ferrule interface. The joint is connected to a 6.5 mm diameter UltraTorr angle-sealed stainless steel bellows. Tube furnace No. 1 5 and tube furnace No. 2 6 are both sleeved on the outside of oxidation bin 3, and tube furnace No. 1 5 is sleeved on the overlap of oxidation bin 3 and pyrolysis bin 2, tube furnace No. 2 6 is sleeved on the outside of copper oxide column, and tube furnace No. 2 6 is located between tube furnace No. 1 5 and vacuum pressure gauge 7; CO2 vacuum capture device 11, CO2 purification device 12, CO2 measuring device 13, CO2 storage device 14 of the present invention are as follows Figure 2As shown, a stainless steel bellows is used to connect one side of the main body of the CO2 vacuum capture device 11 to a conversion joint 9 provided at one end of a flow regulating valve 8. The main body of the CO2 vacuum capture device 11 is a U-shaped stainless steel tube. Liquid nitrogen cooling devices are provided on the two arms of the U-shaped stainless steel tube for cooling CO2 and removing other gases except CO2. Two borosilicate glass tubes are also connected to the middle of the U-shaped stainless steel for capturing CO2. At the same time, the two arms of the U-shaped stainless steel tube extend into the lower part of the borosilicate glass tube; the other side of the main body of the CO2 vacuum capture device 11 is connected to one side of a CO2 purification device 12 (a low-temperature high-vacuum gas purifier, the capture system of which is operated by a low-vacuum vortex, and the purifier is operated by a high-vacuum vortex / molecular pump group) through a stopcock, the other side of the CO2 purification device 12 is connected to one side of a CO2 measuring device 13 (a calibrated barometer) through a stopcock, and the other side of the CO2 measuring device 12 is connected to a CO2 sealing device 14 (a gas sealing tank, i.e., the gas is sealed in a borosilicate glass tube with a welding torch) through a stopcock.

[0031] The carbon isotope detection device provided by the present invention works as follows: the organic sample to be tested is placed in a pyrolysis chamber, and argon is introduced into the pyrolysis chamber 3, and oxygen is introduced into the oxidation chamber 2, while the air pressure of the pyrolysis chamber 3 is made greater than the air pressure of the oxidation chamber 2, so as to ensure that the oxygen in the oxidation chamber will not flow back into the pyrolysis chamber 3; at this time, the No. 1 tubular furnace 5 set at the overlap of the oxidation chamber 2 and the pyrolysis chamber 3 begins to heat up to the pyrolysis of the sample to be tested, and the macromolecular polymers with ionic bonds or weak carbon-hydrogen covalent bonds in the sample to be tested are first fragmented in the pyrolysis chamber, and these small organic molecules produced by pyrolysis are carried into the oxidation chamber 2 by the inert argon carrier gas, and are oxidized to CO2 by oxygen at the high temperature of the No. 2 tubular furnace 6, and pass through the high-temperature oxidation copper column and the low-temperature reduction copper column, and enter the negative pressure environment and are efficiently captured and cold-trapped by the capture device. Subsequently, the CO2 produced by the organic carbon component is purified by a low-temperature high-vacuum gas purifier, and the CO2 micromoles or the carbon content of CO2 are measured by a calibrated barometer, and finally the CO2 is sealed in a borosilicate glass tube with a welding torch.

[0032] The present invention can also extract the organic carbon components produced by anaerobic pyrolysis. After the sample to be tested is pyrolyzed, the residue in the pyrolysis chamber 3 is converted into ultra-high purity black carbon material similar to graphite (such as Figure 3 ), at this time, the argon gas introduced into the pyrolysis chamber 3 is replaced with oxygen, and the ultra-high purity black carbon material is oxidized into CO2 for extraction.

[0033] Experimental Example 2

[0034] Organic carbon component detection experiment: The loess profile samples in the eastern part of the Sui Loess Plateau were detected using the carbon isotope detection device provided by the present invention, including the following steps:

[0035] S1: Place the loess profile samples from the eastern Loess Plateau in a pyrolysis chamber, and introduce argon into the pyrolysis chamber and oxygen into the oxidation chamber;

[0036] S2: raising the temperature of tube furnace No. 1 from room temperature to 750°C, and maintaining the temperature of tube furnace No. 2 at 750°C, to obtain a pyrolysis residue;

[0037] S3: Replace the argon gas in the pyrolysis chamber with oxygen, change the temperature of tube furnace No. 1 to 700°C, maintain the temperature of tube furnace No. 2 at 750°C, burn the pyrolysis residue to obtain CO2, and the CO2 is sequentially passed through the CO2 capture device, CO2 purification device, CO2 measurement device and CO2 storage device to complete the detection.

[0038] The experimental results are as follows Figure 4 As shown, the results show that as long as the temperature is stopped for about 5 seconds, the degradation rate of the organic component decreases or stops, causing the CO2 output rate to drop to the background value, indicating that the biochemical structure organic molecules with stronger carbon bonds will not be degraded by a given temperature, and only at a higher temperature can the components with stronger carbon bonds be degraded. This experiment shows that the organic carbon component provided by the present invention has a group of molecules with the same carbon bonds in a true sense.

[0039] Example 3

[0040] Practical application 1: Four Northeastern black soil farmland profile samples (numbered #23, #26, #28 and #32) were subjected to anaerobic pyrolysis extraction using the carbon isotope detection device provided by the present invention, comprising the following steps:

[0041] S1: Place the northern black soil farmland profile sample numbered #23 in a pyrolysis chamber, and introduce argon into the pyrolysis chamber and oxygen into the oxidation chamber;

[0042] S2: raising the temperature of tube furnace No. 1 from room temperature to 700°C, and maintaining the temperature of tube furnace No. 2 at 750°C, to obtain a pyrolysis residue;

[0043] S3: The argon in the pyrolysis chamber is replaced with oxygen, the temperature of tube furnace No. 1 is changed to 650°C, and the temperature of tube furnace No. 2 is maintained at 750°C. The pyrolysis residue is burned to obtain CO2, which is then tested by passing through the CO2 capture device, CO2 purification device, CO2 measurement device and CO2 storage device in sequence.

[0044] The same method was used to test the Northeastern black soil farmland profile samples numbered #26, #28, and #32. The experimental results are as follows: Figure 5As shown, all surface samples of black soil agricultural land contain ancient organic carbon, indicating that excessive land reclamation has led to the erosion of modern carbon pools and the mixing of old carbon in stratigraphic sediments. The distribution of accelerator carbon-14 ages of the two components (active and inert carbon pools) ranges from about 400 to 13,000 years. The #28 black soil profile has the smallest age variation among different components, and the #32 black soil profile has an old carbon component of 8,000-10,000 years ago at 30 cm, indicating severe erosion. The two groups of carbon pools in the four profiles all show a stable pattern of young active carbon and older inert carbon, indicating that the modern organic carbon production rate of the biosphere is greater than the natural degradation or erosion rate of modern carbon, indicating that the soil ecology is relatively stable.

[0045] Practical Application 2: The carbon cycle of the delta sediments of the modern Yellow River (after 1850) was studied, and the inert carbon components produced by the active-recalcitrant carbon produced by anaerobic pyrolysis and the combustion pyrolysis residue (black carbon) were extracted for accelerator mass spectrometry carbon 14 dating analysis. The anaerobic pyrolysis extraction was performed using the carbon isotope detection device provided by the present invention, which includes the following steps:

[0046] S1: Place modern Yellow River delta sediments in a pyrolysis chamber, introduce argon into the pyrolysis chamber, and introduce oxygen into the oxidation chamber;

[0047] S2: raising the temperature of tube furnace No. 1 from room temperature to 800°C, and maintaining the temperature of tube furnace No. 2 at 750°C, to obtain a pyrolysis residue;

[0048] S3: The argon in the pyrolysis chamber is replaced with oxygen, the temperature of tube furnace No. 1 is changed to 750°C, and the temperature of tube furnace No. 2 is maintained at 750°C. The pyrolysis residue is burned to obtain CO2, and the CO2 is sequentially passed through the CO2 capture device, CO2 purification device, CO2 measurement device and CO2 storage device to complete the detection.

[0049] The experimental results are as follows Figure 6 As shown in the figure, the ages of the two components are much older than the deposition age after the Yellow River was changed in 1850, indicating that the organic carbon carried by the sediment transported by the Yellow River is the organic carbon of the old carbon pool preserved in the geological period. The age difference between the two components of the same sediment sample can be as high as more than 10,000 years. This shows that the same layer of sediment comes from geological bodies in different periods or different regions, and is carried to the Yellow River Delta by the water body in the Yellow River Basin.

[0050] Practical Application 3: The active-recalcitrant carbon (labile-recalcitrant) and the inert carbon (inert) components produced by anaerobic pyrolysis and combustion pyrolysis residue (black carbon) were extracted from the loess profile in Weinan, Shaanxi Province in the southern part of the Loess Plateau and analyzed by accelerator mass spectrometry carbon-14 dating, including the following steps:

[0051] S1: Place the loess profile sample from Weinan, Shaanxi Province in the southern part of the Loess Plateau in a pyrolysis chamber, and introduce argon into the pyrolysis chamber and oxygen into the oxidation chamber;

[0052] S2: raising the temperature of tube furnace No. 1 from room temperature to 750°C, and maintaining the temperature of tube furnace No. 2 at 750°C, to obtain a pyrolysis residue;

[0053] S3: Replace the argon gas in the pyrolysis chamber with oxygen, change the temperature of tube furnace No. 1 to 700°C, maintain the temperature of tube furnace No. 2 at 750°C, burn the pyrolysis residue to obtain CO2, and the CO2 is sequentially passed through the CO2 capture device, CO2 purification device, CO2 measurement device and CO2 storage device to complete the detection.

[0054] The experimental results are as follows Figure 7 As shown, the ages of the two components become older with increasing depth, except for the modern carbon "pollution" phenomenon at 6 meters and 9 meters. This indicates that there is a stable old carbon source or a stable young carbon source that continuously cycles into the soil carbon pool, providing researchers with the opportunity to use other indicators to determine which component provides a reliable carbon component to establish a chronological scale.

[0055] Practical Application 4: The organic carbon covering layer (scientific name: rock varnish) on the surface of rocks exposed in the karst area of ​​Guizhou Province was extracted from the active-recalcitrant carbon (labile-recalcitrant) produced by anaerobic pyrolysis and the inert carbon (inert) components produced by combustion pyrolysis residues (black carbon) and analyzed by accelerator mass spectrometry carbon-14 dating, including the following steps:

[0056] S1: Place the organic carbon cover layer samples on the rock surface exposed in the karst area of ​​Guizhou in a pyrolysis chamber, and introduce argon into the pyrolysis chamber and oxygen into the oxidation chamber;

[0057] S2: raising the temperature of tube furnace No. 1 from room temperature to 750°C, and maintaining the temperature of tube furnace No. 2 at 750°C, to obtain a pyrolysis residue;

[0058] S3: Replace the argon gas in the pyrolysis chamber with oxygen, change the temperature of tube furnace No. 1 to 700°C, maintain the temperature of tube furnace No. 2 at 750°C, burn the pyrolysis residue to obtain CO2, and the CO2 is sequentially passed through the CO2 capture device, CO2 purification device, CO2 measurement device and CO2 storage device to complete the detection.

[0059] The experimental results are as follows Figure 8As shown, the activated carbon-recalcitrant carbon component with weaker carbon bonds is older than the inert carbon component with stronger carbon bonds, which is completely inconsistent with modern physical and chemical structural theories. The present invention summarizes this law as the first typical carbon cycle mode in which organic carbon components are immediately protected by a unique organic matter-iron-manganese film. It is similar to the mechanism of amber preserving organic matter immediately. In the karst landform area, organic carbon molecules emitted in the atmosphere, whether from fossil source emissions or old carbon oxidation respiration in the soil or other organic carbon molecules, are protected by the sticky substances on the surface of the rock and the hard substances formed by the iron-manganese minerals produced by weathering. From the perspective of chronological analysis, the present invention detects the phenomenon that different components with different sources or different ages of occurrence are preserved on the surface of the rock in a superimposed manner.

[0060] Although the specific implementation of the present invention is described in detail in conjunction with the embodiments, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A carbon isotope detection device, characterized in that: The invention comprises an oxygen-free high-temperature pyrolysis device (1), a CO2 capture device (10), a CO2 purification device (11), a CO2 measurement device (12) and a CO2 storage device (13); the oxygen-free high-temperature pyrolysis device comprises a pyrolysis chamber (3), an oxidation chamber (2), a No. 1 tubular furnace (5), a No. 2 tubular furnace (6), a vacuum pressure gauge (7) and a flow regulating valve (8); the pyrolysis chamber (3) and the oxidation chamber (2) are high-temperature resistant quartz tubes, the diameter of the pyrolysis chamber (3) is smaller than the diameter of the oxidation chamber (2), and the oxidation chamber (2) is sleeved on the pyrolysis chamber (3). The pyrolysis chamber (3) is outside the pyrolysis chamber (3) and the two are connected by a three-way joint (4) and a conversion joint (10). The outer end of the pyrolysis chamber (3) is an argon / oxygen inlet, and the inner end with a reduced diameter is a gas outlet. The gas outlet is located in the oxidation chamber (3), and two copper columns are arranged downstream of the gas outlet. One end of the oxidation chamber (2) connected to the three-way joint (4) is an oxygen inlet, and the other end is a gas outlet. The gas outlet is connected to the vacuum pressure gauge (7), and the vacuum pressure gauge (7) is provided with the flow regulating valve (8).

2. The carbon isotope detection device according to claim 1, characterized in that: The two tubular furnaces are both mounted outside the oxidation chamber (2), the No. 1 tubular furnace (5) is mounted at the overlap of the oxidation chamber (2) and the pyrolysis chamber (3), and the No. 2 tubular furnace (6) is located between the No. 1 tubular furnace (5) and the vacuum pressure gauge (7).

3. The carbon isotope detection device according to claim 1, characterized in that: The flow regulating valve (8) is provided with a conversion joint (9), and the conversion joint (9) is connected to the CO2 vacuum capture device (11) through a pipeline.

4. The carbon isotope detection device according to claim 1, characterized in that: The CO2 vacuum capture device (11) comprises a U-shaped main tube and a glass tube; two arms of the U-shaped main tube extend into the lower part of the glass tube and are provided with a liquid nitrogen cooling device; the glass tube is connected to the middle part of the U-shaped main tube.

5. The carbon isotope detection device according to claim 1, characterized in that: The CO2 purification device (12) is a low-temperature high-vacuum gas purifier and is connected to the CO2 capture device (11) via a stopcock.

6. The carbon isotope detection device according to claim 1, characterized in that: The CO2 measuring device (13) is a calibrated barometer and is connected to the CO2 purification device (12) via a stopcock.

7. The carbon isotope detection device according to claim 1, characterized in that: The CO2 storage device (14) is connected to the CO2 measuring device (13) via a stopcock.

8. Application of the carbon isotope detection device described in claims 1 to 7 in geological ecological detection.

9. The use according to claim 8, comprising the following steps: S1: placing organic matter in a pyrolysis chamber, introducing inert gas into the pyrolysis chamber, and introducing oxygen into the oxidation chamber; S2: raising the temperature of tube furnace No. 1 to 700-800° C. and maintaining the temperature of tube furnace No. 2 at 750° C. to obtain a pyrolysis residue; S3: The inert gas in the pyrolysis chamber is replaced with oxygen, the temperature of tube furnace No. 1 is changed to 650-750°C, the temperature of tube furnace No. 2 is maintained at 750°C, and the pyrolysis residue is burned to obtain CO2, which is then detected by passing through the CO2 capture device, CO2 purification device, CO2 measurement device and CO2 storage device in sequence.

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